Premature ejaculation is one of the most prevalent sexual conditions in many men around the world. PE is ejaculation failure, which produces great emotional and relationship distress. Behavioral therapy, drugs and topical anaesthesia are the primary treatments for PE. Some of the most commonly used topical anesthetics for PE are benzocaine and lidocaine. In this article, we are going to see what these two medications are and how they treat PE.
Benzocaine and lidocaine are local anaesthetics that numb the nerve endings in the penis and slow down ejaculation. They come in various formulations, such as creams, sprays and gels, and are rubbed onto the penis prior to sex. These drugs are commonly prescribed to men with PE who require an instant solution to their problem.
Benzocaine has long been applied topically to perform dental and surgical work, but it is now primarily used in the home as a topical anesthetic. It is an effective local anesthetic that blocks the nerve impulses in the penis, decreasing sensitivity and increasing ejaculation time. You can find benzocaine in a variety of strengths, typically between 5% and 10%. It is generally safe and has very little side effects, which makes it a popular treatment among men with PE.
Lidocaine, however, is a stronger local anaesthetic, and acts similarly by interfering with nerve signals in the penis. It is available in various formulations — creams, gels, and sprays, in concentrations ranging from 2% to 10%. Lidocaine is also commonly used in the medical field, for example to numb the skin before an injection or small surgery. It is arguably one of the best topical anaesthetics for PE as it has a longer half-life than benzocaine.
One of the primary differences between benzocaine and lidocaine is the timing of action.
1. pKa Values and Ionization:
Benzocaine is an extremely weak base, and its pKa is roughly 2.5. Lidocaine, on the other hand, has a pKa value of approximately 7.9. This pKa value is crucial because it indicates whether the drug at the physiological pH, around 7.4, is ionised or unionized. Because of this low pKa, only a tiny proportion of benzocaine molecules are united in the body-which is crucial since it allows the drug to quickly travel through nerve membranes and kick in its anaesthetic effect. So with less of the active component that’s capable of going deep into nerve cells, anaesthetics such as benzocaine will take longer to kick in.
However, the higher pKa of lidocaine allows more of its molecules to remain unionised at physiological pH, allowing it to diffuse further through the membranes of the nerves and therefore being faster acting than benzocaine.
2. Routes of Administration:
Another very important element that can cause an action to take place is the route of administration. Although this kind of medication is often applied topically – such as in the event of a sore throat or sunburn – it does, in fact, localise anaesthesia on skin or mucous membranes. These in turn decrease the speed at which benzocaine is absorbed into and acts on the nerve fibres, which explains the slower onset of the drug.
There are several other routes of administration for lidocaine. Although lidocaine is a topical medication, infiltration and nerve block procedures often employ lidocaine. These procedures enable lidocaine to reach the nerve fibres much more effectively, dramatically reducing the time for drug entry. Because it will be able to directly reach the nerve endings, it will enable the patient to feel relief from the pain much more quickly than benzocaine.
3. Lipid Solubility and Diffusion:
The physical properties of the anesthetics, particularly their lipid-solubleness, play a major role in determining onset time. Lidocaine is more lipid-soluble than benzocaine. Lidocaine’s high degree of lipid solubility means that it passes rapidly across nerve membranes. This would be why lidocaine is more effective and fast acting- it blocks, during these relatively short timescales, the sodium channels containing the pain signal.
The reduced lipid permeability of benzocaine, by contrast, might make the drug less effective at entering the nerve tissue as rapidly, and this may be one reason why it takes so long to cause anaesthesia.
Another important factor to consider when comparing these two medications is their potential side effects.
Benzocaine and lidocaine can have a number of side effects that range from minor to severe, depending on the dose, route, duration of use, and factors affecting the patient. Common side effects of both agents include:
1. Local tissue effects: Both benzocaine and lidocaine may lead to local irritation, erythema, edema and pruritus at the application site.
2. Methemoglobinemia: Particularly benzocaine is known to have a tendency towards methemoglobinemia, a condition in which abnormally high levels of the pigment methemoglobin in the blood can cause hypoxia and cyanosis. This is particularly dangerous in children and those with a genetic or acquired defect in methemoglobin reductase.
3. Allergies: Both benzocaine and lidocaine can cause hypersensitivity reactions in rare cases. Urticaria, angioedema, bronchospasm and anaphylaxis are some of the possible symptoms.
4. Cardiovascular effects: When dispensed parenterally, lidocaine can result in cardiovascular adverse reactions including hypotension, bradycardia and arrhythmias, especially at very high doses or in patients with compromised cardiac function.
5. Central nervous system side effects: both benzocaine and lidocaine are prone to central nervous system side effects such as dizziness, lightheadedness, sedation, and seizures, especially when taken in large amounts or in combination with other central nervous system depressants.
A number of studies have compared the performance of benzocaine and lidocaine for PE. According to one experiment, the drugs worked equally well at slowing down ejaculation, although lidocaine took longer to kick in. In a separate trial, lidocaine was more successful in shortening the time to ejaculation and increasing sexual satisfaction than benzocaine. These findings lead us to believe that lidocaine may be a better treatment for PE men, particularly those who have longer periods of control of their ejaculation.
Conclusion:
Benzocaine and lidocaine, in a nutshell, are good topical PE anaesthetics. Benzocaine acts rapidly, whereas lidocaine takes a longer time to do so. For men who want to feel more in control of their ejaculations, lidocaine is the best option as it lasts much longer. But it can be accompanied by more numbness or less feeling. Of course, a physician would know the right one to use based on the situation and your preference. Additional therapies, other than topical anaesthetics, can be employed in combination with behavioural therapy to achieve greater success.
